Derby Talk

Derby Talk is a forum for Pinewood Derby, Awana Grand Prix, Kub Kar Rally, Shape N Race Derby, Space Derby, Raingutter Regatta and other similar races where a child and an adult work together to create a race vehicle and a lot of fun and memories

I'm not really understanding the difficulty. The USB port on the Arduino is the physical connection to the computer. The firmware that you load into the Arduino through that same USB connection is what will do all of the timing and reporting to the computer.

gpraceman wrote:I'm not really understanding the difficulty. The USB port on the Arduino is the physical connection to the computer. The firmware that you load into the Arduino through that same USB connection is what will do all of the timing and reporting to the computer.

Thank you. I wasn't positive that the Arduino UNO sent the data over the USB port on the UNO.

I might make up one of these, as I already have a Arduino Uno board on hand. It might come in handy with testing any changes in GPRM.

Anyways, I am a bit confused on the display boards. If I am understanding things correctly, these displays are supposed to daisy chain off of each other. So, I am trying to think how to easily connect these together without a bunch of wire splicing.

It is not readily apparent how the Arduino will know which display goes to which lane. You mention jumpers in your documentation, but I don't see anything on the Adafruit site about them.

gpraceman wrote:If I am understanding things correctly, these displays are supposed to daisy chain off of each other. So, I am trying to think how to easily connect these together without a bunch of wire splicing.

(A note to those using the shield PCB from me - the display pin order on the PCB does not match the pin order on the Adafruit displays - the SDA and SCL pins are swapped.)

gpraceman wrote:It is not readily apparent how the Arduino will know which display goes to which lane. You mention jumpers in your documentation, but I don't see anything on the Adafruit site about them.

gpraceman wrote:Is there an easy implementation for a single 7-digit display per lane? For my purposes, I don't really need the times displayed.

I don't know of any single digit 7-segment LEDs pre-made with the controller board like the Adafruit displays.

Depending on how many lanes you have it would be pretty simple to alter the software to just display the finish order across one (<= 4 lanes) or two (5 or 6 lanes) Adafruit 4 digit displays. The numbers would not physically line up with the lanes but it would work for testing.

That is an idea. All but one of the timers in my collection are 4 lanes, which makes testing GPRM changes easier (don't have to keep changing the number of lanes in GPRM). Anyways, I just need a test unit, not a real race timer setup, so that would work. Though, those backpack displays aren't too expensive, so I may still go that route.

I do like how those display modules come in red, blue, green, and yellow in addition to white. It would be cool to have the timer lane colors match a track with colored lanes.

I've built one of these and it works pretty well in my tests. In a few months I'll use it in our Derby.

My question is: how do you protect the IR receiver?

I just soldered wires directly onto the leads coming out of the receiver and basically bent that into a 90 for insertion beneath the track. I've already had a couple break on me. Is there some better way to do this?

It's fine for now since I'm ok twiddling with it but I'd like to make something bulletproof so it can live on in the pack well after my son has moved on.